Conventionally, it was general to apply an artificial denture or a bridge as a treatment method for the teeth loss area, edentulous area.
However, an implant treatment has been developed as a new dental treatment method in recent years and attracts attention. The implant treatment inserts a metal as an artificial tooth root into the alveolar bone or the gnathic bone and then, places an artificial tooth being similar with natural tooth over the metal making it as the foundation.
In comparison with the artificial denture, the implant tooth is superior in stability, and has enough biting force. Further, being different from the bridge, it is unnecessary for the implant tooth to give loads to other teeth or to whittle the adjacent healthy teeth in order to support itself, and it has advantages with no unnatural appearance and with capability of biting like the human's own tooth.
However, it is necessary for the implant treatment that the alveolar bone or the gnathic bone remains enough for supporting the implant tooth sufficiently.
The alveolar bone is an organ that depends upon tooth. Namely, the alveolar bone does not exist in a site without tooth, and does not form in the case where there is no tooth by nature. Moreover, without caring after exodontia makes the alveolar bone insensible against stimulation, absorbed and thinner.
Furthermore, caused by serious disease around teeth or accident and so on, the alveolar bone and the gnathic bone may be absorbed in circumferential textures or may be damaged.
Accordingly, it is difficult to insert the implant tooth with a condition as it is in the case where the alveolar bone or the gnathic bone is not sufficient in the amount or the situation.
Therefore, before carrying out the implant treatment, for example, a manipulation of increasing the thickness of an alveolar bone by means of a method referred to as a socket lift or a sinus lift in order to enable to insert a implant in the case where a palatine alveolar bone thinned.
Further, with regard to a mandible, well known is either an invention of compensating the thinned bone by filling granules of hydroxyapatite and so on or a manipulation of transplanting an own bone respectively into a site where the bone is poor.
By the way, the hydroxyapatite is a kind of calcium phosphate represented by a chemical formula [Ca10(PO4)6(OH)2] and is an main composition composing bone, having adaptability with an own bone, etc., and further having properties of fixing into an organ in vivo by absorption after the lapse of time. Besides, the hydroxyapatite ceramics is widely employed as a suitable material for the artificial bone conventionally from the viewpoints of superior strength characteristic, advantage in the harmlessness to a living body.
U.S. Pat. No. 6,340,648 B1 discloses that a porous sintered body of ceramics which comprises spherical pores communicating with one another substantially throughout the body with relatively high porosity is preferable, among the hydroxyapatite ceramics, because osteoblast and related cells are easy to intrude into most of the pores and as a result, nutrients are supplied sufficiently to the cells.
Further, Japanese Patent Application Laid-Open No. 6(1994)-197947 proposes an implant, etc., formed by applying a ceramics coating of a crystallized glass mainly consisting of Diopside over the surface of a metallic substrate. The proposed implant is highly evaluated in its affinity with a living body and its mechanical strength.
Furthermore, Japanese Patent Application Laid-Open No. 2001-245903 proposes gnathic bone prosthesis materials having tooth root with simple structure, easily treatable, and giving capability of not only prosthesis of bone but also regeneration of tooth easily.
However, even the implant described in the Japanese Patent Application Laid-Open No. 6(1994)-197947 has a base metal for the implant itself remains covered by ceramics coating layer consisting of the crystallized glass. As described above, the ceramics being artifact, besides, being ceramics of the crystallized glass requires so long time until it functions as bone that a burden charged to a patient might be considerably great.
Further, it is extremely difficult to provide gnathic bone prosthesis materials having tooth root described in Japanese Patent Application Laid-Open No. 2001-245903 fitting a patient because it has a structure of preparedly inserting an implant into a compact apatite and at the same time, integrated with an artificial gnathic bone.
Accordingly, it is ideal that the implant is inserted directly in the own bone in order to support the implant stably and to obtain a good biocompatibility. Therefore, regarding with an implant insertion site, a practical patient-friendly technology for forming an alveolar bone or a gnathic bone sufficiently in the amount and the condition for strengthening the bone tissue was eagerly demanded.